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Stock-Based Compensation, Stock Award and Incentive Plan and Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Employee service share-based compensation, aggregate disclosures [Abstract] |  |  |
Number of common stock available for issuance (in shares) | 880,000 |  |
Term of stock options granted under Plan | 10 years |  |
Vesting period, generally, for stock options granted under the plan | 3 years |  |
Share based compensation costs | $ 6.2 | $ 8.1 | $ 6.3
Stock Options [Member] |  |  |
Employee service share-based compensation, aggregate disclosures [Abstract] |  |  |
Share based compensation costs | 4.2 | 4.1 | 3.5
Tax benefit of share-based compensation | $ 1.1 | $ 1.1 | $ 1.4
Forfeiture rate assumed | 8.20% | 8.71% | 7.38%
Weighted average grant date fair value for stock options granted (in dollars per share) | $ 25.79 | $ 30.28 | $ 14.34
Weighted average grant date fair value for stock options vested (in dollars per share) | $ 21.33 | $ 18.45 | $ 20.94
Total intrinsic value of stock options exercised | $ 3.3 | $ 11.7 | $ 4.9
Weighted Average Assumptions [Abstract] |  |  |
Expected life | 6 years 2 months 12 days | 6 years 4 months 24 days | 6 years 6 months
Interest rate | 2.50% | 2.04% | 1.72%
Volatility | 30.33% | 36.61% | 36.75%
Expected dividend yield | 0.26% | 0.26% | 0.54%
Stock Options [Roll Forward] |  |  |
Balance, beginning of year (in shares) | 996,839 |  |
Granted (in shares) | 191,147 |  |
Exercised (in shares) | (98,945) |  |
Canceled (in shares) | (34,782) |  |
Balance, end of year (in shares) | 1,054,259 | 996,839 |
Exercisable, end of year (in shares) | 688,652 |  |
Weighted Average Exercise Price Per Share [Abstract] |  |  |
Balance, beginning of year (in dollars per share) | $ 48.21 |  |
Granted (in dollars per share) | 76.09 |  |
Exercised (in dollars per share) | 33.83 |  |
Canceled (in dollars per share) | 65.74 |  |
Balance, end of year (in dollars per share) | 54.04 | $ 48.21 |
Exercisable, end of year (in dollars per share) | $ 46.17 |  |
Weighted Average Remaining Contractual Life [Abstract] |  |  |
Outstanding options, end of year | 6 years 1 month 6 days |  |
Exercisable options, end of year | 4 years 10 months 24 days |  |
Aggregate Intrinsic Value [Abstract] |  |  |
Outstanding options, end of year | $ 7.8 |  |
Exercisable options, end of year | $ 6.9 |  |
Additional Information [Abstract] |  |  |
Closing stock price on last business day of the period (in dollars per share) | $ 51.34 |  |
Weighted average intrinsic value of options exercised (in dollars per share) | $ 33.10 | $ 32.95 | $ 32.34
Unrecognized stock-based compensation expense | $ 4.5 |  |
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized | 3 years |  |
Nonvested Stock Options [Member] |  |  |
Stock Options [Roll Forward] |  |  |
Balance, beginning of year (in shares) | 400,393 |  |
Granted (in shares) | 191,147 |  |
Vested (in shares) | (195,055) |  |
Canceled (in shares) | (30,878) |  |
Balance, end of year (in shares) | 365,607 | 400,393 |
Weighted Average Exercise Price Per Share [Abstract] |  |  |
Balance, beginning of year (in dollars per share) | $ 58.94 |  |
Granted (in dollars per share) | 76.09 |  |
Vested (in dollars per share) | 56.17 |  |
Canceled (in dollars per share) | 65.13 |  |
Balance, end of year (in dollars per share) | $ 68.86 | $ 58.94 |

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